Telegraph system



Jan. 25; 1944. W. LANG 2,340,065

TELEGRAPH SYSTEM 7 Filed March 24, 1943 2 Sheets-Sheet 1 /5 cwsss onau/wr sum z .9 4 5 STOP ----m/m-a CAM RIM 1 1}: guspficma CAM momPOSITIONS MARKING emu/r SPAC/NG bps/v Q MARKING. u: SPACIIVG INVENTOPMK'LASNG A WORNEV' Jan. 25, 1944.

W. Y. LANG TELEGRAPH SYSTEM I Filed March 24, 1943 2 Sheets-Sheet 2INI/SNTOR WKLANG AT TORNEV Patented Jan. 25, 1944 TELEGRAPH SYSTEMWilmarth Y. Lang, ".lowaco, N. J., assignor to BellTelephoneL'aboratories, Incorporated, New York, N.Y.,.a-corporation of New YorkApplicationjMarchjM, 1943,.Seria1 No. 480,319

8 Claims.

This invention relates to telegraphyapparatus and mechanisms and moreparticularlyto animproved telegraph receiving selector.

.Incertain telegraph switchingsystems and in other systems it issometimes desirable to employ ax'blank signal, i. e., a code-combinationin which all of the significant selecting impulses are spacing-toperform some switching or other function. When such signals are employedfor switching-or other functions difficulty is sometimes encountered dueto the fact that the usual single magnet selecting mechanism employedfor. telegraph reception and control of switching and other functionsare unable to distinguishbetween a.-so-

calledblank code combination-and a break signal or an open lineconditionwhich ,isfrequently encountered .due to momentary disturbances-'to which telegraph transmission lines are frequently subjected.

Accordingly one of the objects of this inven-.

of at least two different signaling .-.conditions' which are transmittedover the-transmissionsystem. In start-stop or simplex telegraph systemsadditional synchronizing pulses 'are transmitted before and after eachcodegroup :of' pulses in order to maintain synchronismbetweenthe:

transmitting apparatus and the-receivingcapparatus connected to thesystem. pulse transmitted before the codepulses isusually'called the.start pulse and'is-so-rreferred'to hereinafter. The synchronizingpulsetransmitted after the code pulses is usually called the .stop pulse..Thezterm stop:pulse is vusedzin this specification to reierto thexpulsefollowing the code pulses of each'codecombination independently of thecharacter of the -pulse .in this position. A code combination thusincludes the synchronizingpulses and the codepulses.

' Generally the lineis closed during .idleperiods during the time thetransmission .circuitis established and this condition isfrequentlycalled a marking condition. An open pulse, usually called aspacing pulse, is transmittedbefore each groupof codepulses as a startpulse. .-A-fter.each code combination amarking stop pulse istransmittedand then a spacing start pulse is trans- The synchronizing mitted beforethe next group of code pulsesetc.

Whena blank code combination is transmitted over the line a spacingstart impulse followed by five spacing selecting impulses aretransmitted over the line and this in turn is followed by a marking stopimpulse.

When the line is interrupted due to hits or other circuit disturbancesthe stop pulse will also be spacing.

In accordance with the present invention blank codecombinations aredistinguished from open lines or hits depending upon whether or not astop pulse is marking or spacing. If the stop pulseis marking theequipment will respond to the code combination as a blank code combina-.tion whereas if the stop pulse is spacing the equipment will not respondto the open line or hit as a blank code. In other Words, the switch ingcircuits or special functions will not be performed when an open linecondition develops or a hit .or break signal is received over the linebut will be performed when a blank code combinationis received.

The foregoing and other objects and features of this invention, thenovelty of which is set forth in the claims appended hereto, may be morereadily understood from the following specification when read withreference to the attached drawings in which:

Fig. 1 shows in schematic form the equipment and circuits in accordancewith this invention for preventing the actuation of circuits can-' inaccordance with the present invention together with graphs of both ablank signal and an open line condition or break signal;

Fig. 3 shows a perspective View of one embodiment of the inventionapplied to a common type of telegraph selector; and

.Fig. 4;shows typical telegraph receiving and selecting mechanisms towhich the invention may be applied.

Referring now to the drawings, Fig. 1 shows the circuit arrangements andapparatus in S8118." matic .form in accordance with one embodiment ofthe present invention, 1 i represents the transmitting contacts of atransmitting instrument while I2 represents some break contacts whichmay be employed to transmit break signals over line H]. The breakcontacts l2 and the transmitting contacts II are connected by means ofline ill to a telegraph receiving instrument.

Line It] may extend between different stations Line I may also includeany suitable type of repeating and terminal equipment normally employedin the respective types of telegraph transmission. Line Iii may includeswitching apparatus and also extend through one or more switchingcenters or central station or exchanges.

It is also within the scope of the present invention to have thetransmitting contacts II at the same station or closely adjacent thereceiving instrument provided with the improved selecting arrangement inaccordance with the present invention. As shown in Fig. 1, line Illextends through windings of relays I3and I5. Of course, line III couldextend to a terminal relay and then acircuit from the terminal relay orrepeater ex tend through the line winding of relays I3 and I5. Relay I3is the usual line relay and controls a selecting magnet I4 of thereceiving telegraph instrument which may be of the type sometimes calleda teletypewriter and in the case of shorter lines or when repeaters areemployed the windings selector magnet I4 of the receiving instrument maybe connected directly in series with line Ill instead of having thesignals repeated from line If! to the selector magnet I4 by means ofrelay I3. Relay I5 has also been provided for actuating control magnetI9 as will be described herein.

As will be apparent to those skilled in the art in case sufiicientcurrent flows over line ID, or in the local circuit from repeater ofline I0, the winding of magnet I9 may be connected directly in, seriesto this line in the same manner as the selector magnet I 4 may beconnected in series with the line. It will also be apparent to thoseskilled in the art that magnet I9 and selector magnet l4 may becontrolled from the same receiving or repeating relay by connectingthese magnets in parallel to the marking contact of the repeating relay.However. in order to reduce the contact load and wear each of themagnets is provided with a separate relay in the embodiment of theinvention shown in Fig, 1.

The selector mechanism controlledvby the selector magnet I4 may beof'any suitable type such as those disclosed in U. S. Patents 1,745,633granted to S. Morton et al. on February 4, 1930, and 1,904,164 alsogranted to S. Morton et al. on April 18, 1933, 2,255,794 granted toLake, September 16, 1941, and 1,937.376 granted to Zenner on November28, 1933.

Such selector mechanisms comprise a selecting cam barrel 35 as shown inFig. 3 provided with a cam for each of the significant selectingimpulses and the various levers cooperating with it which cause thereceiving mechanism to selectively print or record characters inaccordance with the received telegraph signals. The manner of operationof this equipment is described in detail in the above-identifiedpatents. which patents are hereby made part of this application as iffully included herein. Inasmuch these mechanisms work in their, normalmanner a detailed description of their operation would serve no usefulpurpose if repeated herein but would serve only to obscure the presentinvention.

In accordance with the present invention an additional cam I6 is mountedupon the same cam barrel 35 as the selecting cams and is caused torotate with the selecting cams. The additional cam I6 in the embodimentshown in the present invention is a ring type of cam and cooperates withthe projection ll of lever I8 in such a manner that the lever I1 ismaintained in either one .of the two positions depending upon itssetting at a particular instant in the cycle of operation of the cambarrel 35. As is well understood by those skilled in the art, cam barrel35 is rotated through a friction clutch 30 under control of releaselevers and mechanisms actuated by the selector magnet I4 as shown inFigs. 1, 3 and 4. Upon the reception of a spacing start impulse, magnetI4 releases and in turn releases cam barrel 35 for rotation through onerevolution. During this revolution the selecting mechanism of thereceiving instrument is conditioned to selectively controlthe recordingof the character or function represented by the received telegraphsignals. Near the end of this revolution of cam drum 35,

the printing, perforating, or other function or' apparatus of thereceiving device will set into operation and cause it to record orfurther respond to the received signal.

As indicated in Fig. 2 a blank signal comprises a spacing start pulse 5and spacing significant impulses followed by a stop pulse. This signalis represented by the heavy line 21 shown in Fig. 2. An open line due totrouble conditions or the break signal transmitted over line I0comprises a spacing start signahspacing selecting impulses, and also aspacing stop signal. In order to differentiate between the blank signaland an open line or a break signal it is necessary to determine whetheror not a stop pulse is marking or spacing.

Added cam I6 together with lever l8 and the controlling magnet I9 havebeen provided to determine whether or not the stop pulse is marking orspacing. The contour of cam I6 and its orientation with respect to thesignificant pulses of a telegraph signal is illustrated indiagrammatic-form by line I6 of Fig. 2. The projection ll of leverI8fwhich cooperates with the cam is also indicated in Fig. 2.

By reference to the development of cam I6 shown in Fig. 2 together withthe location of projection I'I it is evident that during the stop pulsethe projection I! of lever I8 is released and permitted to assume eitherone or the other of two positions dependin upon whether or not magnet I9is energized or deenergized during this time.

As shown in Figs. 1, 2 and 3 the projection IT is located approximatelyat the center of the stop interval assuming that the cam I6 in Figs. 1and 3 is shown in its rest position. It is to be understood that thisparticular showing of th relative positions of projector I1 and theopening cam I6 is forthe purpose of illustration only. As will bereadily understood by those skilled in the art the usual arrangement isto release the selectable or controlled element for only a shortinterval of time during a predetermined portion of the pulse interval inorder to secure the best results. Also the length of the opening in camI5 should be appreciably less than the entire pulse interval.Furthermore, it will be desirable to accurately time the interval duringwhich the test of the stop pulseis made. In order to select thisinterval the'control magnet I9 and the pivot 3I supporting lever I8 aremounted upon a movable plate 20, the position of which relative to thecam barrel 35 may be changed by loosening screws 22 and sliding plate 20around the cam barrel so'screws 22 slide in slot 34. 1

'Thu's by properly-adjustin the position "of plate 2fl'the particularportio'n of the stop pulse desired to control the positioning of lever|8 may lie-selected. 'Normally le ver 8'will not 'be released in thestopposition of thecam'drum35. Instead therim portion-of'the cam It willhave passed the projection I! and the lever -|8- when the cam drum35'cornes torest. 'Inthis 'manner'theoperation-oflcvr Bis in no wayeiiecte'd by'the time interval *betweensuccessive characters or pulses.

-Of"course,-as will-be readil -apparent to those skilled-in the art, ifit is so-d'esiredthe orientation, that is, the position of'p1ate20 maybeso-regulatedtogether with the openingin-cam l6 that projection may befree to'mo'vewhen' thecam drum-35 is atres't.

Contacts 23 are operated in response to the reception of any signal inwhich all of the five significant pulses are spacing. The manner'inwhich these contacts are operated is well understood by those skilled inthe art and is described in greater detail in United States Patents2,120,235 and 2,112,234 granted to Beattie et al. on June 14, 1938, andMarch 23, 1938, respectively, the disclosures of which patents arehereby made a part of this application as if fully included herein. Theblank pull bar of the specific type of telegraph mechanism shown in Fig.4 is selected in response to a blank signal and the selection of thispawl bar through its upper extension causes contacts 23 to bemomentarily closed, as is well understood by those skilled in the art.

However, the closure of contacts 23 does not take place during thereception of the blank code combination but during the succeedingrevolution of the cam drum 35. This time relation is well understood, isdue to the construction of the mechanisms, and is brought about by thefact that the actual printing or recording of each code combinationcannot start until the entire code combination has been received. Thusthe recording of one code combination takes place during the receptionof the succeeding code combination. Similarly contacts 23 are closed inresponse to. the reception of one code combination during the receptionof the succeeding code combination since these contacts closeconcurrently with the printing or with the recording of a character orduring the performance of the function represented by the codecombination.

Assuming first that a blank code combination is received, reception ofthis code combination will cause all of the five selecting elements tobe positioned to their spacing position and cause the selection of theblank pull bar which in turn causes contacts 23 to be momentarilyoperated shortly after the completion of the reception of the blank codecombination.

Since the blank code combination was transmitted a marking stop pulsewill immediately follow the fifth spacing impulse. Magnet I9 will,therefore, be operated during the time the projection I! of lever I8 isfree from the rim of cam l6. Consequently projection will be heldoutside of the rim of cam l6. With projection I! held outside of the rimof cam l6, contacts 2| will remain closed so that when the contacts 23later close a circuit is completed for the operation of relay 25 frombattery through the winding of relay 25 and closed contacts 23 and 2| toground. As shown in Fig. 1, relay 25 completes a circuit for maintainingitself operated under control of key 24 and completes a circuit forlighting a signal lamp 26.

the art thatthe-simultaneous closurexof contacts 23-and 2| inresponse''to thereception of a'blank signal may'cause'the operation of otherrelays When'it is desired torelease relay 25 key' 24- will 'be operated-momentarily which interrupts the locking circuit of relay 25 andpermits this relay to release.

If, however, a break signal, an open line or a hit, which is longerthan-the complete codecombinationpis received overthe line the fiveselecting pulses will again cause the selection of the blank pull barand the later actuation 'of contacts 23. In this case, however, aspacing pulse will be received immediately following the No. 5 selectingpulse. Consequently magnet l9 will be released or deenergized when theprojection H of lever I8 is freed by cam l6. Spring 32 will then causeprojection I! to move inside the rim of cam 6 where it will be heldduring the succeeding revolution of the cam drum 35. As shown in thedrawing, with the projection I! held inside the rim of cam Hi the outerend 33 at lever 8 will cause contacts 2| to open. Consequently when theblank contacts 23 close shortly after the completion of the firstrevolution of the cam drum 35 the circuit of relay 25 will not becompleted because contacts 2| are held open all during the entiresucceeding revolution of cam drum 35 and thus of cam l6. In this mannerthe circuit of relay 25 is completed only when a blank code combinationis transmitted but is not completed when a break signal or momentarycircuit interruption causes break signals to be received by thereceiving selector.

It also will be apparent to those skilled in the art that this inventionis not limited to distinguishing between code combinations havingmarking and spacing stop pulses but may be employed to distinguishbetween code combinations having either marking or spacing pulses in anyone of the other positions of the combination.

What is claimed is:

1. In a permutation code selector, apparatus responsive to the receptionof a permutation code having all the significant code impulses thereofspacing for closing a contact and other apparatus responsive to afollowing spacing control impulse for opening the circuit through saidcontact.

2. In a permutation code selector, apparatus responsive to the receptionof a permutation code having all the significant code pulses thereofspacing for closing a contact and other apparatus responsive to afollowing spacing pulse for preventing the completion of any circuitthrough said contact.

3. In a permutation code selector, apparatus responsive to apredetermined code combination for performing a switching operation, andselective equipment responsive to the succeeding pulse for controllingthe performance of said switching operation.

4. In a start-stop permutation selector, apparatus responsive to the,reception of a predetermined code for selecting electrical circuits, andcontrol circuits responsive to the following stop pulse for controllingthe selected circuit.

5. In a start-stop permutation selector, a rotative element, equipmentfor releasing said element for rotation through one revolution in re- Itwill beat-onceapparent; to those skilled in sponse to a start pulse,mechanically operative selective apparatus responsive to the followingcode pulses for selecting electrical apparatus, and other mechanicallyselective apparatus responsiveto the stop pulse for controlin-g theselected apparatus.

6. A telegraph start-stop permutation code selector comprising arotatable element, apparatus responsive to a start pulse to cause therotation of said element through one revolution, a two position stoppulse member, a stop pulse cam rotated by said rotatable element andcooperating with said stop pulse member, and apparatus to position saidmember in either of its positions under control of a stop pulse.

a 7. In a telegraph start-stop selector a two position member, arotatable cam for holding said member in either of its two positionsduring the major portion of the revolution, and apparatus responsive toa stop pulse to position said mem-- her in one of its positions.

8. In a start-stoptelegraph permutation code element under control ofthe stop pulse, and

equipment for operating the selected operatable member under control ofsaid two position element.

WILMAR'I'H Y. LANG.

